Mercedes-Benz Forum banner

1 - 20 of 25 Posts

·
Registered
2001 SL500
Joined
·
287 Posts
Discussion Starter #1
Basically, from a standstill I accelerate very lightly and let go of the gas pedal, engine braking takes place like normal, BUT, if I start accelerating again, slowly or quickly, I get a bang/knock as soon as I press on the gas. It’s loudest from the outside of the car.

There’s a slight jerk accompanying this banging. Anyone know what the hell this is? Sounds like it’s coming from transmission or driveshaft...
 

·
Registered
1992 Mercedes 300SL R129. 94 S320 Mercedes w140
Joined
·
65 Posts
Is the knock in the rear, transmission area or like it is a broken mount in the engine compartment?
 

·
Registered
1999 ML320, 1998 SL500
Joined
·
857 Posts
If you decide to replace your engine mounts there is a very detailed instruction writeup from Mercedes. You need to be sure to follow it to avoid radiator and other damage. Also, the rear mount is probably good but I think you should replace it anyhow.
 

·
Registered
M113 SL500
Joined
·
514 Posts
You know, honestly, you come on here soliciting advice, and it seems like you find reasons to not check things that people suggest. In the end, you end up taking your car in to repair shops to do the inspecting and work for you. Even with the bad luck you've had with some of the repair shops, they're not any worse than asking people to guess at what your issue is over the internet. So, why don't you skip the soliciting guesses step and take it into a shop and get it checked out if you're not going to do it yourself.
 

·
Registered
2001 SL500
Joined
·
287 Posts
Discussion Starter #13
You know, honestly, you come on here soliciting advice, and it seems like you find reasons to not check things that people suggest. In the end, you end up taking your car in to repair shops to do the inspecting and work for you. Even with the bad luck you've had with some of the repair shops, they're not any worse than asking people to guess at what your issue is over the internet. So, why don't you skip the soliciting guesses step and take it into a shop and get it checked out if you're not going to do it yourself.
Ultimately, I’ll have a shop check what people are suspecting.

I never gave a reason not to check anything, I’m just wondering how suspension can be related if the problem is confined to specifically acceleration after engine braking.

I thought this was a forum... Am I not allowed to think/question? Also, please stay on topic when responding to posts.
 

·
Registered
1989 W124 260E
Joined
·
1,792 Posts
I t is a must to have this problem looked at on a four poster lift .
And the first item i would look at is this rubber coupling on drive shaft or as some call it prop shaft .
First picture is the start .And final picture is after the noise was ignored .
maxresdefault.jpg
flex_damage_2_bf32640dde4b08c370ebabc0d464998d657ebe0a.jpg
 

·
Outstanding Contributor
R129 500 SL 1991
Joined
·
1,044 Posts
^^ Plinker. Ditto. 👍
If I am not mistaken that looks like one of those substandard URO flex disks that were being talked about a few years back, and which let go with very little warning?
Could you declare your source of these photos please?
 

·
Registered
2001 SL500
Joined
·
287 Posts
Discussion Starter #16
I t is a must to have this problem looked at on a four poster lift .
And the first item i would look at is this rubber coupling on drive shaft or as some call it prop shaft .
First picture is the start .And final picture is after the noise was ignored . View attachment 2626752 View attachment 2626753
Wow that looks horrid. Checking of the rubber coupling has been noted
 

·
Outstanding Contributor
R129 500 SL 1991
Joined
·
1,044 Posts
I thought this was a forum... Am I not allowed to think/question? Also, please stay on topic when responding to posts.
Well said 👍 but I wouldn’t give too much heed when brownhaus is in one of his moods. I am sure he means well. I have profited from some of his more coherent posts on BW. Probably best to ignore the rants though.

Please continue to use and enjoy this great forum.
 

·
Registered
1996 SL 500
Joined
·
46 Posts
I t is a must to have this problem looked at on a four poster lift .
And the first item i would look at is this rubber coupling on drive shaft or as some call it prop shaft .
First picture is the start .And final picture is after the noise was ignored . View attachment 2626752 View attachment 2626753
Flex Disk and not from a R129
Basically, from a standstill I accelerate very lightly and let go of the gas pedal, engine braking takes place like normal, BUT, if I start accelerating again, slowly or quickly, I get a bang/knock as soon as I press on the gas. It’s loudest from the outside of the car.

There’s a slight jerk accompanying this banging. Anyone know what the hell this is? Sounds like it’s coming from transmission or driveshaft...
Basically, from a standstill I accelerate very lightly and let go of the gas pedal, engine braking takes place like normal, BUT, if I start accelerating again, slowly or quickly, I get a bang/knock as soon as I press on the gas. It’s loudest from the outside of the car.

There’s a slight jerk accompanying this banging. Anyone know what the hell this is? Sounds like it’s coming from transmission or driveshaft...
By your description, it is in the drive line, Flex disc front, center bearing, flex disc back and differential, oil leak ?
 

·
Registered
94 SL320 98 SL500 99 SL600
Joined
·
1,049 Posts
Another spot to check is the 4 diagonal braces 2 front and 2 rear I believe they are T55 bolts. those need to be extremely tight. Normally they will clunk when turning at low speed. But I'm betting on control arm bushings. very common on the R129.
 
1 - 20 of 25 Posts
Top